Department of Molecular Neurobiology, Brain Research Institute, Niigata University, Niigata, 951-8585, Japan.
Department of Biological Sciences, Graduate School of Medicine, Kyoto University, Kyoto, 606-8501, Japan.
Sci Rep. 2022 Jul 28;12(1):12917. doi: 10.1038/s41598-022-17174-3.
Rats elicit two types of ultrasonic vocalizations (USVs), positive (30-80 kHz; high pitch) and negative (10-30 kHz; low pitch) voices. As patients with schizophrenia often exhibit soliloquy-like symptoms, we explored whether an animal model for schizophrenia is similarly characterized by such self-triggered vocalizations. We prepared the animal model by administering an inflammatory cytokine, epidermal growth factor (EGF), to rat neonates, which later develop behavioral and electroencephalographic deficits relevant to schizophrenia. EGF model rats and controls at young (8-10 weeks old) and mature (12-14 weeks old) adult stages were subjected to acclimation, female pairing, and vocalization sessions. In acclimation sessions, low pitch USVs at the mature adult stage were more frequent in EGF model rats than in controls. In the vocalization session, the occurrences of low pitch self-triggered USVs were higher in EGF model rats in both age groups, although this group difference was eliminated by their risperidone treatment. Unlike conventional negative USVs of rats, however, the present low pitch self-triggered USVs had short durations of 10-30 ms. These results suggest the potential that self-triggered vocalization might serve as a translatable pathological trait of schizophrenia to animal models.
大鼠可发出两种类型的超声波（USVs），即正（30-80 kHz；高音调）和负（10-30 kHz；低音调）声。由于精神分裂症患者常表现出独白样症状，我们探索了精神分裂症的动物模型是否也具有类似的自我触发发声特征。我们通过给新生大鼠施用炎性细胞因子表皮生长因子（EGF）来制备动物模型，这些大鼠后来表现出与精神分裂症相关的行为和脑电图缺陷。在幼年（8-10 周龄）和成年（12-14 周龄）阶段，EGF 模型大鼠和对照组大鼠进行适应、雌性配对和发声会话。在适应阶段，成年大鼠的低频 USVs 在 EGF 模型大鼠中比在对照组大鼠中更为频繁。在发声会话中，尽管 risperidone 治疗消除了组间差异，但在两个年龄组中，EGF 模型大鼠低频自我触发 USVs 的发生率均更高。然而，与传统的大鼠负性 USVs 不同，本研究中的低频自我触发 USVs 持续时间较短，为 10-30 ms。这些结果表明，自我触发发声可能成为一种可转化的精神分裂症动物模型的病理特征。
